The invention relates to a method for supporting multimedia services via a radio interface between a mobile telecommunication system with radio-oriented transceiver apparatuses and a mobile terminal device with radio-oriented transceiver apparatuses, as well as a corresponding mobile telecommunication system and a corresponding mobile subscriber terminal device.
In telecommunication there is an increasing effort to enable universal personal telecommunication, which means that the services of a telecommunication system should be made available to a subscriber of such a system over as wide an area as possible. As a result, telecommunication systems with a radio interface or with a line-bound interface to subscriber terminal devices are subject to the demand of offering as many services as possible with suitable quality--also, in particular, for mobile subscribers via the air interface. Mobile communication systems comprise for example a radio interface to/from mobile stations of mobile radio subscribers, via which signaling signals and useful signals are transmitted. The signals are thereby produced at the transmit side and at the receive side, and are sent out by transceiver apparatuses of the telecommunication system or, respectively, of the mobile stations. For a supporting of multimedia services, such as for example video conferences, in telecommunication systems with radio interface there is the problem that the radio interface represents a bottleneck with respect to the transmission bandwidth. Its radio-oriented resources for signal transmission via air must thus be allocated very carefully and sparingly.
In addition, the mobile stations are relatively small and light, for which reason the possibilities for the display of images according to a multimedia service at the mobile terminal device are limited. For this reason, currently multimedia services are in any case offered in telecommunication networks with a line-bound interface, and up to now have not been supported by telecommunication systems with radio interface. Nonetheless, there already exist considerations relating to a prototype of a multimedia mobile terminal device--see "Mobile multimedia by MAVT--A starting point of many applications," distributed at the RACE Mobile Telecommunications Summit, Lisbon, 22-24 November 1995 (publication date on the last page 08/95).
From European reference EP-0 619 679 A1, an arrangement and a system are known for a multi-local teleconference with several subscribers who communicate with one another exclusively via wire-bound terminal devices in a line-bound telecommunication system (e.g. ISDN network). The essential step of the known teleconference is thereby that a speech localization unit detects the speech signals of several subscribers at various locations, and an image combination unit combines the image signals of the speaking subscribers to form a resulting image signal. This resulting image signal enables the simultaneous display of images of all speaking subscribers at particular zones of the display screen of each wire-bound terminal device involved in the conference.
From the article "The enabling technology for multi-application domestic wireless systems," PTR Philips Telecommunications Review 52 (1995) October, no. 4, pages 9 to 11, a DECT wireless system is known as a video conference system for "in-house" applications (domestic). The wireless system uses an air interface between a wireless base station and a wireless terminal device, but this is however not comparable with the radio interface of a mobile radio system with respect to the use and allocation of the radio-oriented resources for signal transmission. The wireless house videotelephone system has a limited range, whereby the DECT base station receives signals from the fixed network via a wire-bound videophone, and sends signals via the air interface to a television screen for the graphic display of the signals. This design can be used (e.g. as a DECT-based home security system) in situations in which videotelephones are not yet available.